A sea serpent, 45 meters long lies hidden under
the surface of the water. The animal is bent horizontally and
vertically, but doesn't touch itself anywhere, even diagonally. Its
head (the top red square), tail (the bottom red square) and a few
other parts (the blue squares) are visible. Can you figure out the
snake's exact position?

To include a square into the snake's body, simply click it to color
into blue. To exclude a square from the snake's body click the blue
square again (except those already provided on the grid) and it will
be turned into grey. Clicking a grey square brings it back to the
initial blank state. Only the blue squares, along with the red head
and tale, are considered to be parts of the snake.

There is a counter to the left of the grid showing how many squares
are currently selected as the snake's body, i.e. how many of them are
colored in blue. At the start the counter already displays the number
of all the initial visible squares, including the head and the tale.
You only need to make the number equal the length of the snake, i.e.
45.

Use the Restart button each time you want to start solving the
challenge from the initial point.